0:00:12.680,0:00:16.720
Brrr! Whose idea was[br]it to camp in winter?

0:00:16.720,0:00:18.900
And why is winter

0:00:18.900,0:00:21.560
so much colder and[br]darker than summer?

0:00:21.560,0:00:24.680
To understand this, we[br]need to explain how

0:00:24.680,0:00:26.300
the tilt of the[br]Earth's axis

0:00:26.300,0:00:28.780
affects the amount[br]of sunshine we get,

0:00:28.780,0:00:31.260
and explain how[br]the tilt of

0:00:31.260,0:00:32.820
the Earth's axis affects

0:00:32.820,0:00:35.120
how warm the sun feels.

0:00:35.120,0:00:38.440
The Earth spins[br]on its axis.

0:00:38.440,0:00:41.820
The fact that it takes[br]24 hours to complete

0:00:41.820,0:00:46.600
one spin helps us[br]explain day and night.

0:00:46.840,0:00:49.060
But it is the tilt of

0:00:49.060,0:00:50.420
the Earth's axis that will

0:00:50.420,0:00:52.500
help us understand[br]the seasons.

0:00:52.500,0:00:56.840
It is tilted at an[br]angle of 23.4 degrees,

0:00:56.840,0:00:58.080
and the Earth takes

0:00:58.080,0:01:00.220
one year to orbit the sun.

0:01:00.220,0:01:02.560
Different parts[br]of the Earth are

0:01:02.560,0:01:05.320
tilted towards the[br]sun as it orbits.

0:01:05.320,0:01:07.680
In winter, the[br]northern hemisphere

0:01:07.680,0:01:09.500
is tilted away[br]from the sun.

0:01:09.500,0:01:11.240
This means fewer[br]hours each

0:01:11.240,0:01:13.360
day are spent in daylight.

0:01:13.360,0:01:15.980
In summer, the[br]northern hemisphere

0:01:15.980,0:01:18.040
is tilted towards the sun.

0:01:18.040,0:01:19.760
This means more hours

0:01:19.760,0:01:22.440
each day are spent[br]in daylight.

0:01:23.880,0:01:25.960
The tilt of the Earth

0:01:25.960,0:01:27.460
also affects[br]the angle that

0:01:27.460,0:01:28.800
the sun shines onto

0:01:28.800,0:01:30.860
different parts[br]of the Earth.

0:01:30.860,0:01:33.040
In the summer, the sun is

0:01:33.040,0:01:34.280
shining more directly

0:01:34.280,0:01:35.920
at the northern[br]hemisphere.

0:01:35.920,0:01:37.640
In the winter, the sun

0:01:37.640,0:01:39.900
shines at more[br]of an angle.

0:01:39.900,0:01:42.880
The sun appears[br]higher in the sky in

0:01:42.880,0:01:45.920
summer and lower[br]in the winter.

0:01:45.920,0:01:48.720
The angle of the sun[br]in the winter spreads

0:01:48.720,0:01:51.400
the sun's rays over[br]a larger area.

0:01:51.400,0:01:53.420
They are less[br]concentrated,

0:01:53.420,0:01:56.280
and so it feels colder.

0:01:56.280,0:01:59.820
So, the Earth's tilt[br]really does mean

0:01:59.820,0:02:01.220
it's better to[br]go camping in

0:02:01.220,0:02:03.760
the UK in summer.

0:02:03.760,0:02:06.580
In winter, the[br]Northern hemisphere

0:02:06.580,0:02:08.440
is tilted away[br]from the sun.

0:02:08.440,0:02:10.500
We have fewer[br]hours of daylight,

0:02:10.500,0:02:12.440
and the sun's rays[br]are spread over

0:02:12.440,0:02:15.420
a larger area,[br]meaning it's colder.

0:02:15.420,0:02:17.880
In summer, the[br]northern hemisphere

0:02:17.880,0:02:19.640
is tilted towards the sun.

0:02:19.640,0:02:22.460
We have more hours of[br]daylight and the sun

0:02:22.460,0:02:24.020
shines more directly onto

0:02:24.020,0:02:26.720
us, meaning it's warmer.

0:02:27.440,0:02:30.840
I know which one I prefer.

0:02:30.840,0:02:34.840
[bird song]